<!DOCTYPE HTML>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>innerBefore</title>
</head>
<body>

<ul id="test">
    <li>JavaScript</li>
    <li>HTML</li>
</ul>

<script type="text/javascript">

    var otest = document.getElementById("test");
    //在script 标签内补充代码，实现创建一个新li标签，内容为"php",并将新创建的li插入到内容为HTML的标签前。
    var newnode = document.createElement("li");
    newnode.innerHTML = "php";
    otest.insertBefore(newnode, otest.childNodes[0]);
</script>

</body>
</html>